In the field of the plastic films, "hot melt" films are well known. French Pat. No. FR 2,523,143 describes an adhesive whose composition contains at least about 35% by weight ethylene based copolymers, at least one vinylic ester, and from 0.5 to 20% of a copolyetheresteramide.
European patent application No. 312,968 describes the use of adhesive films of the "hot melt" type for the assembly of elements of a ski structure. These films are basically composed of a thermoplastic polymer and of an adhesion promoting agent, such as a silane or an epoxy resin.
SUMMARY OF THE PRESENT INVENTION
An object of the present invention is a film comprising a new composition, adapted for adhesion, which possesses improved adhesion properties, and may be applied to a variety of materials and elements, preferably in the production of an article of manufacture, such as a ski.
Another object of the invention is to improve the thermal retention of the adhesion of elements of a structure, such as a ski, that is formed using the adhesive film of the thermoplastic materials of the present invention.
An advantage of the films of thermoplastic materials of the present invention is that they are more economical to manufacture and implement when compared to currently known films.
The present invention relates to films or sheets of thermoplastic material, adapted for adhesion, having a composition comprising at least one thermoplastic elastomer (TPE) based on polyamides and a copolymer of modified olefins.
The present invention is directed to a process for assembling elements of a ski structure which involves adhering a first element having a junction surface to at least a second element having a junction surface by placing at least one adhesive layer between junction surfaces of the first element and the second element, and placing at least one thermoplastic film having a composition comprising a polyamide based thermoplastic elastomer and a copolymer of modified olefins between said adhesive layer and the junction surface of said first element to result in a ski structure.
The present invention is also directed to a ski structure which is composed of at least a first element having a junction surface; a thermoplastic film having a composition comprising a polyamide based thermoplastic elastomer and a copolymer of modified olefins placed on the junction surface; an adhesive layer applied to the thermoplastic film; and at least a second element having a junction surface adhered to the adhesive layer.
For purposes of the processes and resultant structures, such as skis, of the present invention the copolymer of modified olefins preferably includes either at least one member selected from the group consisting of olefin monomers, or at least one comohomer selected from the group consisting of vinylic esters of saturated carboxylic acids, saturated mono-carboxylic acids, saturated di-carboxylic acids, esters of saturated mono-carboxylic acids, esters of saturated di-carboxylic acids, salts of saturated mono-carboxylic acids, salts of saturated di-carboxylic acids, anhydrides of saturated di-carboxylic acids, and anhydrides of saturated di-carboxylic acid. Preferably, the copolymer of modified olefins is an ethylene-propylene grafted copolymer.
In accordance with the present invention, the thermoplastic elastomer includes at least about 50% by weight of the composition, and preferably at least about 60% by weight of said composition. For the purposes of the present invention the ethylene propylene grafted copolymer may be grafted by a member selected from the group consisting of carboxylic acid, an anhydride of carboxylic acid, and a salt of carboxylic acid. Preferably, the copolymer includes at least two monomers of different olefins, and more preferably the copolymer is selected from the group consisting of maleic ethylene and propylene dienes, and maleic ethylene and propylene rubbers, such as a maleic ethylene and propylene diene, or a maleic ethylene and propylene rubber, wherein the maleic ethylene and propylene rubber comprises between about 0.1% to about 2% by weight maleic anhydride.
For the purpose of the present invention, the copolymer of modified olefins may include at least one modified copolyolefin selected from the group consisting of statistical copolymers and sequenced copolymers, wherein the copolyolefins comprise at least one member selected from the group consisting of i) at least two monomers of different olefins, and ii) at least one comonomer selected from the group consisting of vinylic esters of saturated carboxylic acid, saturated mono-carboxylic acids, saturated di-carboxylic acids, esters of saturated mono-carboxylic acids, esters of saturated di-carboxylic acids, salts of saturated mono-carboxylic acids, salts of saturated di-carboxylic acids, anhydrides of saturated di-carboxylic acids, and anhydrides of saturated di-carboxylic acids, wherein said olefins represent at least 50% of the total weight of said copolymer, and preferably comprise at least 60% by total weight of said copolymer, and wherein the weighted ratio of ##EQU1## is greater than about 50%, and preferably is greater than about 60%.
In accordance with the present invention, the polyamide based thermoplastic elastomer includes a copolymer selected from the group consisting of statistical copolymers and sequenced copolymers, wherein the sequenced copolymers comprise polyetheresteramides, and the polyetheresteramides comprise sequenced polyamides having an average molecular weight of between about 500 and about 10,000, and preferably between about 600 and about 5,000, and wherein the polyetheresteramides comprise polyethers which have an average molecular weight of between about 200 and about 6,000, and preferably between about 600 and about 3,000.
For purposes of the present invention, the adhesive layer may include a material selected from the group consisting of resin and a foam, wherein the thermoplastic film is interspersed between the adhesive layer and the junction surface. Preferably, the adhesive layer includes a member selected from the group consisting of epoxy adhesives, polyester adhesives, and polyurethane adhesives, wherein the adhesive layer and the second element comprise a pre-impregnated, partially cross-linked assembly. The junction surface of the first element may include at least one member selected from the group consisting of polyamides, polyethylenes, polyethylene terephthalates, polybutadiene terephthalates, polypropylenes, aluminum, processed aluminum, steel, and metal alloys, and preferably a polyamide film. The first element is preferably an exterior element of a ski.
A process of the present invention also involves subjecting the ski structure to heat to cross-link the thermosettable adhesive.
For purposes of the present invention, the polyamide-based thermoplastic elastomer comprises a polyetheramide, preferably, wherein the polyetheramide comprises a polyetheresteramide. The modified copolyolefin may be selected from the group consisting of maleic ethylene and propylene rubbers, and maleic ethylene, propylene and diene copolymers.
For the purposes of the present invention the thermoplastic film may include at least one men, her selected from the group consisting of fillers, pigments, dyes, and additives, preferably wherein the fillers are present in amounts up to about 50% by weight and more preferably up to about 40% by weight of the polyamide-based thermoplastic elastomer and copolyolefin. The adhesive may be a thermosettable adhesive which is selected from the group consisting of epoxy resins, polyester resins, and polyurethane resins.
In accordance with the present invention, the thermosettable adhesive and the second element may comprise a pre-impregnated, partially cross-linked assembly. Also, the junction surface of the first element may include at least one material selected from the group consisting of polyamide, polyethylene, polyethylene terephthalate, polybutadiene terephthalate, polypropylene, aluminum, processed aluminum, aluminum alloys, steel, and metal alloys, and preferably wherein the first element is a polyamide film. The first element may be a decorative element or a protective element for a ski.
A process of the present invention also involves placing the first element, the polyamide-based thermoplastic film and the second element in a mold, injecting an expandable polyurethane foam into the mold and permitting the polyurethane foam to harden and adhere to the polyamide-based thermoplastic film and the first element.
A process of the present invention also involves coextruding the first element and the polyamide film in a single step.
The present invention is also directed to a film adapted for adhesion, which includes at least one polyamide based thermoplastic elastomer; and at least one modified copolyolefin selected from the group consisting of statistical copolymers and sequenced copolymers, said copolyolefins comprising at least one member selected from the group consisting of i) at least two monomers of different olefins, and ii) at least one comonomer selected from the group consisting of vinylic esters of saturated carboxylic acid, saturated mono-carboxylic acids, saturated di-carboxylic acids, esters of saturated mono-carboxylic acids, esters of saturated di-carboxylic acids, salts of saturated mono-carboxylic acids, salts of saturated di-carboxylic acids, anhydrides of saturated di-carboxylic acids, and anhydrides of saturated di-carboxylic acids, wherein said olefins represent at least 50% of the total weight of said copolymer, and preferably at least 60% by total weight of said copolymer, preferably wherein the weighted ratio of ##EQU2## is greater than about 50%, greater than about 60%.
A process of the present invention also involves assembling elements of a composite material by adhering at least one first element having a junction surface and a second element having a junction surface by placing an adhesive layer of a material selected from the group consisting of a resin and a foam between junction surfaces of the first element and the second element, interspersing a thermoplastic film having a composition comprising polyamide based thermoplastic elastomer and a copolymer of modified olefins between the adhesive layer and the junction surfaces, preferably wherein the adhesive layer comprises epoxy adhesives, polyester adhesives, and polyurethane adhesives, and the adhesive layer and the second element comprise a pre-impregnated partially cross-linked assembly. The junction surface of said first element may comprise at least one member selected from the group consisting of polyamides, polyethylenes, polyethylene terephthalates, polybutadiene terephthalates, polypropylenes, aluminum, processed aluminum, aluminum alloy, steel, and metal alloys, and is preferably a polyamide film. The first element preferably comprises an upper element for decoration and protection of a wind surfer.
In accordance with the present invention, the first element and the polyamide film may be coextruded in a single step.
The process of the present invention may involve placing the first element, the thermoplastic film, and the second element in a mold, and injecting an expandable polyurethane foam into said mold and permitting the foam to expand, harden and adhere to the adhesive film and to the first element.
A process of the present invention also involves forming a thermoplastic film having a composition comprising a polyamide based thermoplastic elastomer and a copolymer of modified olefins into a packaging material, such as sheaths and bags.